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Power systems worldwide are experiencing rapid evolvements with a massive increase of renewable generation in order to meet the ambitious decarbonization targets. A significant amount of renewable generation is from Distributed Energy Resources (DERs), upon which the system operators often have limited visibility. This can bring significant challenges as the increasing DERs' can lead to network constraints being violated, presenting critical risks for network security. Enhancing the visibility of DERs can be achieved via the provision of communication links, but this can be costly, particularly for real time applications. Digital Twin (DT) is an emerging technology that is considered as a promising solution for enhancing the visibility of a physical system, where only a limited set of data is required to be transmitted with the rest data of interest can be estimated via the DT. The development and demonstration of DTs requires realistic testing and validation enviorment in order to accelerate its adoption in the industry. This paper presents a real time simulation and hardware-in-the-loop (HiL) testing platform, specifically designed for prototyping, demonstrating and testing DTs of DERs. Within the proposed platform, a software-based communication emulator is developed, which allows the investigation of the impact of communication latency and jitter on the performance of DTs of the DERs. Case studies are presented to demonstrate the application of the developed DT prototyping process and testing platform to enable frequency control using the DTs, which provide valuable learnings and tools for enabling future DTs-based solutions. [ABSTRACT FROM AUTHOR]

Integrated full electric propulsion systems are being introduced across both civil and military marine sectors. Standard power system analysis packages cover electrical and electromagnetic components but have limited models of mechanical subsystems and their controllers. Hence, electromechanical system interactions between the prime movers, power network, and driven loads are poorly understood. This paper reviews available models of the propulsion drive system components: the power converter, motor, propeller, and ship. Due to the wide range of time constants in the system, reduced-order models of the power converter are required. A new model using state-averaged models of the inverter and a hybrid model of the rectifier is developed to give an effective solution combining accuracy with speed of simulation and an appropriate interface to the electrical network model. Simulation results for a typical ship maneuver are presented. Index Terms--Electromechanical interactions, marine, propulsion, rectifier models.

This paper proposes a robust pilot protection scheme based on waveform similarity that restricts the influence of outliers in fault line identification. By comparing two refactoring currents constructed using the time-domain sampling values of currents at the two terminals of a transmission line, a waveform similarity algorithm called the Kendall's Tau coefficient (KTC) is employed to distinguish two different datasets of a protected transmission line. A reliable fault identification is realized under different fault types, distances, and resistances. Proposed criteria that are robust against to current transformer saturation, synchronization error, and noise are proposed. The KTC is based on simply the rank order instead of the metric value and thus limits outliers to a moderate level, ensuring protection safety in cases where outliers that cannot be eliminated completely are included in the current waveforms. The simulation results demonstrate the excellent performance of the proposed robust pilot protection scheme. [ABSTRACT FROM AUTHOR]

Online diagnostics and online condition monitoring are important functions within the operation and maintenance of a power plant. When there is knowledge of the relationships between the raw data and the underlying phenomena within the plant item, typical intelligent system-based interpretation algorithms can be implemented. Increasingly, health data is captured without any underlying knowledge concerning the link between the data and their relationship to physical and electrical phenomena within the plant item. This leads to the requirement for dynamic and learning condition monitoring systems that are able to determine the expected and normal plant behavior over time. This paper describes how multi-agent system technology can be used as the underpinning platform for such condition monitoring systems. This is demonstrated through a prototype multi-agent anomaly detection system applied to a 2.5-MW diesel engine driven alternator system. Index Terms--Cooperative systems, decision support systems, generators, intelligent systems, monitoring, multi-agent systems.

The installed capacity of non-synchronous devices (NSD), including renewable energy generation and other converter-interfaced equipment is expected to increase and contribute a large proportion of total generation capacity in future power systems. Concerns have been expressed relating to operability and stability of such systems, since NSD are typically decoupled from the grid via power electronic devices and consequently reduce the 'natural' inertia, short-circuit levels and damping which are inherently provided by synchronous machines. This study establishes the instantaneous penetration level (IPL) limits of NSD connected to a model power system in terms of steady-state stability beyond which the system condition becomes unstable. The NSD used in this example will be a conventional dq-axis current injection (DQCI) convertor model. The study introduces a set of system 'viability' criteria relating to locking signal in converter phase-locked loop, frequency, rate of change of frequency and voltage magnitude, which are used to determine the IPL limits. Among many factors which can affect the IPL limits, the impact of frequency and voltage droop slopes and filter time-constants of DQCI converter is quantified. Finally, a frequency domain visualisation method referred here as 'network frequency perturbation' is introduced to provide additional insight into contributions of individual generators. [ABSTRACT FROM AUTHOR]

The installed capacity of non‐synchronous devices (NSD), including renewable energy generation and other converter‐interfaced equipment is expected to increase and contribute a large proportion of total generation capacity in future power systems. Concerns have been expressed relating to operability and stability of such systems, since NSD are typically decoupled from the grid via power electronic devices and consequently reduce the 'natural' inertia, short‐circuit levels and damping which are inherently provided by synchronous machines. This study establishes the instantaneous penetration level (IPL) limits of NSD connected to a model power system in terms of steady‐state stability beyond which the system condition becomes unstable. The NSD used in this example will be a conventional dq‐axis current injection (DQCI) convertor model. The study introduces a set of system 'viability' criteria relating to locking signal in converter phase‐locked loop, frequency, rate of change of frequency and voltage magnitude, which are used to determine the IPL limits. Among many factors which can affect the IPL limits, the impact of frequency and voltage droop slopes and filter time‐constants of DQCI converter is quantified. Finally, a frequency domain visualisation method referred here as 'network frequency perturbation' is introduced to provide additional insight into contributions of individual generators. [ABSTRACT FROM AUTHOR]